This document provides an introduction to pharmacology and drug classification. It defines what a drug is, how drugs work in the body through pharmacodynamics and pharmacokinetics, and why people can react differently to drugs. It describes the key components of drugs and how they are classified both chemically and legally according to their potential for abuse and medical usage. Common drug types like depressants, stimulants, opioids, and cannabis are outlined.

1. INTRODUCTION
CLASSIFICATION
BY :MEMOONA HAROON
DRUGS-PHARMACEUTICAL
COMPOUNDS

2. INTRODUCTION TO
PHARMACOLOGY
 The study of drugs or chemicals and the effects they
have on living animals is called pharmacology.
 It explains what drugs are, what they do to body functions
and what the body does to them.
 It also explains why a person may experience side effects
when they take drugs and why there is such a wide
spectrum of differences between drug actions in different
people.

3. WHAT IS A DRUG?
 A drug is any substance (other than food that provides
nutritional support) that,
when inhaled, injected, smoked, consumed, absorbed via
a patch on the skin, or dissolved under the tongue causes a
temporary physiological (and often psychological) change in the
body.
 A pharmaceutical drug, also called a medication or medicine, is
a chemical substance used to treat, cure, prevent,
or diagnose a disease or to promote well-being.
 Once these chemicals are absorbed into the systemic
circulation they bind with certain proteins and this changes the
functioning of the cell slightly.
 Example: anticancer drugs bind to proteins on the surface of
cancer cells this stimulates the cells to die. In this case cell
death is the physiological action of the drug.

4. WHAT IS PRESENT IN A DRUG?
 The chemical in the drug that affects physiological
functioning is the active ingredient of the drug. For most
drugs, the amount of chemical needed to cause an effect is
very small, often as small as 5 micrograms; this is 0.005%
of a gram.
 Along with this, inactive substances are also packed with it
so that its not vulnerable to loss.
 Examples of inactive ingredients are lactose, dyes
and gluten.

5. CONTINUED
 These inactive ingredients have no effect on the
functioning of cells.
 Rather these inactive ingredients work to bind the
drug together and lubricate the drug so it is easy
to swallow(in case its taken orally).

6. HOW DO DRUGS WORK?
 Our bodies are largely controlled by proteins.
 Proteins exist in many different forms in the body and
have many different functions.
 Each protein has a specific function and is quite specific to
the cell type that it acts on.
 For example, there are specific types of proteins
called receptors. Receptors are embedded on the cell
surfaces, there are different receptors for different types of
cells. A liver cell will have different receptors than a cardiac
cell. The receptor binds to other proteins and chemicals on
the outside of the cell and this in turn creates a change in
the functioning of the cell.

7. CONTINUED
 Proteins also act as drug targets. In order for a drug
to exert an effect it needs to be bound to a protein.
 This can be thought of as a lock and key system;
where the drugs are the key and the protein is the
lock. Once the drug is bound in this lock and key
mechanism it can have one of two main influences
over the cell. It can produce a change in response or
it can stop a normal response of the cell.
 Drugs that produce a change in the cell functioning
are called agonists. Drugs that stop a normal
function of the cell are called antagonists.

9. PHARMACODYNAMICS:WHAT DO
DRUGS DO TO THE BODY?
 The interaction of drugs with cellular proteins,
receptor or enzymes to control the changes in
physiological functions of particular organ is
known as pharmacodynamics.
 It is concerned with three following things;
 Drug-receptor interaction(binding)
 Signal transduction(mechanism of action and
pathway)
 Dose-response (effect)

10. PHARMACOKINETICS;WHAT THE
BODY DOES TO DRUGS?
 Pharmacokinetics is the study of what happens to
drugs once they enter the body. The main stages
include:
 The absorption of the drug into the blood and
across cell membrane to enter the cells.
 The distribution of the drug throughout the body.
 The metabolism or breakdown of the drug, and
 The excretion of the drug from the body.

14. Why do the effect of drugs vary in
different people?
 Many of the reasons that we see such a wide and diverse
range of efficacies of drugs across people are that drugs
work differently in different people.
 This means that the drugs will produce same qualitative
results(same end results and same side effects) but the
quantity of these differ largely which depends upon following
factors;
 Ethnicity
There are quite substantial differences in drug metabolism
between people of different ethnicities. Asians are usually
more sensitive to most drugs than Caucasians and
Caucasians are more sensitive then afro-carrabeans.

15. Continued…
 Age
Elimination of the drug from the body is directly influenced
by age. Newborns and elderly experience the effects of
drugs for longer and the drug takes a lot longer to be
eliminated from the body.
Newborns
When babies are born to term, their renal function is very
quick to establish similar levels to adults within one week
after birth. If the baby is born prematurely it can take 8
weeks or more to reach the level of enzymes necessary. If
drugs are given before the renal function is at this level, the
drug elimination from the body takes a lot longer and so do
the effects of the drugs.
Elderly
Renal filtration rate begins to decline at 20 years of age
and by 50 years of age it has declined by 50%. This again
will affect the elimination of drugs from the body.

16. Continued..
 Genes
The differences in our genes are also an
important determinant of variability in what our
bodies to do the drugs.
 Disease state
There are many different disease states that
affect pharmacokinetics.
Examples: Diseases of the liver and kidneys will
affect drug metabolism and excretion whereas
diseases of the gastroenterological systems will
affect the absorption of drugs.

28. NOMENCLATURE OF DRUGS
 There are three ways to name a drug:
 Chemical name
 Non proprietary name(generic name)
 Proprietary name(trade name)

33. CLASSIFICATION OF DRUGS
THERAPEUTIC PHARMACOLOGICAL CHEMICAL
AMALGATED LEGAL

36. CHEMICAL CLASSIFICATION
 Each of the regulated drugs that act on the central nervous
system or alter our feelings and perceptions can be classified
according to their physical and psychological effects.
The different drug types include the following:
 Depressants. Drugs that suppress or slow the activity of the
brain and nerves, acting directly on the central nervous system
to create a calming or sedating effect. This category includes
barbiturates (phenobarbital, thiopental, butalbital),
benzodiazepines
(alprazolam, diazepam, clonazepam, lorazepam, midazolam),
alcohol, and gamma hydroxybutyrate (GHB). Depressants are
taken to relieve anxiety, promote sleep and manage seizure
activity.
 Stimulants. Drugs that accelerate the activity of the central
nervous system. Stimulants can make you feel energetic,

37. CONTINUED..
 Hallucinogens. Also known as psychedelics, these
drugs act on the central nervous system to alter our
perception of reality, time, and space. Hallucinogens
may cause us to hear or see things that don’t exist or
imagine situations that aren’t real. Hallucinogenic
drugs include psilocybin (found in magic mushrooms),
lysergic acid diethylamide (LSD), peyote, and
dimethyltryptamine (DMT).
 Opioids. These are the drugs that act through the
opioid receptors. Opioids are one of the most
commonly prescribed medicines worldwide and are
commonly used to treat pain and cough. These
include drugs such
as heroin, codeine, morphine, fentanyl, hydrocodone,

38.  Inhalants. These are a broad class of drugs with the
shared trait of being primarily consumed through
inhalation. Most of the substances in this class can exist
in vapor form at room temperature. As many of these
substances can be found as household
items, inhalants are frequently abused by children and
adolescents. These include substances such as paint,
glue, paint thinners, gasoline, marker or pen ink, and
others. Though ultimately all of these substances cross
through the lungs into the bloodstream, their precise
method of abuse may vary but can include sniffing,
spraying, huffing, bagging, and inhaling, among other
delivery routes.
 Cannabis. Cannabis is a plant-derived drug that is the
most commonly used illicit drug worldwide. It acts through
the cannabinoid receptors in the brain. Cannabis is
abused in various forms including bhang, ganja, charas,
and hashish oil.

39. LEGAL CLASSIFICATION OF
DRUGS
 The Controlled Substances Act established five
classifications, or schedules, for drugs regulated by law.
These classifications are broken down based on their
potential for abuse and if they have a legitimate medical
use:
 Schedule I include the drugs that have a high potential
for abuse, that have no currently accepted medical use in
treatment in the United States, and that there is a lack of
accepted safety for use of the drug under medical
supervision. Drugs such as cannabis, ecstasy, GHB,
heroin, LSD, mescaline, and methaqualone are included in
Schedule I.

40. Continued…
 Schedule II includes drugs that have a high potential for
abuse, have currently accepted medical use in treatment
in the United States or currently accepted medical use with
severe restrictions, and that the abuse of may lead to
severe psychological or physical dependence. Drugs such
as amphetamine, cocaine, fentanyl, hydromorphone
oxycodone, and hydrocodone are included in Schedule II.
 Schedule III includes drugs that have a potential for
abuse less than the drugs or other substances in
schedules I and II, have a currently accepted medical use
in treatment .

41. and that the abuse of may lead to moderate or low
physical dependence or high psychological dependence.
Drugs such as anabolic steroids, buprenorphine, and
ketamine are included in Schedule III.
 Schedule IV includes drugs that have a low potential for
abuse relative to the drugs or other substances in
schedule III, have a currently accepted medical use in
treatment and that the abuse of may lead to limited
physical dependence or psychological dependence relative
to the drugs or other substances in schedule III. Drugs
such as benzodiazepines, modafinil, and tramadol are
included in Schedule IV.

42.  Schedule V includes drugs that have a low
potential for abuse relative to the drugs or other
substances in schedule IV, have a currently
accepted medical use in treatment and that the
abuse of may lead to limited physical dependence or
psychological dependence relative to the drugs or
other substances in schedule IV. Drugs such as
diphenoxylate (in combination with atropine),
lacosamide, and pregabalin are included in Schedule
V.

43. BIOPHARMACEUTICAL
CLASSIFICATION SYSTEM
 A scientific framework for classifying drugs
depending on their aqueous solubility & intestinal
permeability.
 Established by Gordan amidon and etc.